Yes, definitely the Enterprise Edition (x64)! I am a part time student and got my hands on the EE through Microsoft DreamSpark. I wanted to make sure that I was using the most feature rich version of the software, and I didn't want to go to the hassle of installing a Server OS.
Thx for coming back, though not sure your answer has helped as you didn't confirm you installed the SQL Engine, and not just the SQL Server Management Tools. Also, when I look on DreamSpark, I just see SQL2008 R2 Developer ed available...
Just of note, Developer edition is
a full feature-rich version, ie, its Enterprise ed but with a different licencing requirement and has been set so that it will load onto Client OS's as well as Server OS's. Apart for the OS thing, Developer ed is to all intents and purposes, Enterprise ed.